feat: shared loading state + cleanup loading state management (#5835)

* feat: implement shared loading bar component and polished loading states across the app

* feat: align loading states + ensureQueryData changes

* fix: lint + bugs

* fix: skeleton for manage servers page

* fix: merge conflict fix

packages/ui/src/providers/loading-state.ts

@@ -0,0 +1,27 @@
+import type { Ref } from 'vue'
+
+import { createContext } from './create-context'
+
+/**
+ * Cross-platform loading-state contract injected by the host app.
+ * Consumed by the shared `LoadingBar` and `ReadyTransition` components.
+ */
+export interface LoadingStateProvider {
+	/** True iff at least one active load token is registered. */
+	readonly pending: Readonly<Ref<boolean>>
+	/** Host-level kill switch (e.g. disable the bar during a splash screen). */
+	readonly barEnabled: Readonly<Ref<boolean>>
+	/** Begin a tracked load. Returns a unique token; pair with `end(token)`. */
+	begin(): symbol
+	/** End a previously-begun load. Idempotent — unknown or repeat tokens are silently ignored. */
+	end(token: symbol): void
+	/** Fire a synthetic load that auto-releases after `durationMs` (default 500ms). For manual-refresh buttons. */
+	beginManual(durationMs?: number): void
+	/** Toggle the bar at the host level. */
+	setEnabled(enabled: boolean): void
+}
+
+export const [injectLoadingState, provideLoadingState] = createContext<LoadingStateProvider>(
+	'root',
+	'loadingState',
+)